Abstract:
Sample sites was distributed on the Santiago river before, in and after of the Aguamilpa Dam construction between 1992 and 1997. The objetive was the detection of the impacts on the plankton community with the application of the Water Quality Index (WCI), Secuential Comparison Index (SCI), the Shannon-Weiner Index (H') and the Saprobiological Index (S) on the phytoplanctonic community. The physicochemical water quality was interpreted with de Ecological Criteria for the Aquatic Life Protection in the Freshwater and Coastal Water of Mexico. The results showed organic contamination in the water column, where Scenedesmus, Oscillatoria y Alaucoseira crenulata was the bioindicators in these environmental conditions. The dam showed eutrophic tendence due at the nutrients (N). The phytoplankton community doesn't change.